Yeah, I've been asked out for a dare before too. I said no. I didn't really like the guy and he didn't like me like me like that.

My response: If you say yes knowing that it's a dare then, yeah. I think you should go (you said you would didn't you?), but... if you discover that it was a dare and you don't want to go any more tell him. You deserve to get that off your chest. It's not right for him to do that. (Use words carefully!)